Russian Syria withdrawal could spell end for Assad

Russian warplanes and military personnel at the the Syrian Hmeymim airbase AAP)

An expert says Russia withdrawing its troops from Syria could be a sign the tide is turning against Bashar Al Assad.

University of Otago politics professor William Harris says Russia may be frustrated with the Syrian regime's uncertain position.

"The Syrian regime really is short of manpower on the ground, and that may be something that’s frustrating the Russians as well -- that the regime is simply having difficulties mustering up the manpower of its own forces."

Russian warplanes began leaving Syria yesterday after President Vladimir Putin announced that Russia has achieved its aims in the war-torn country.

Putin's announcement of the withdrawal of the "main part" of Russian armed forces in Syria has led Assad's opponents to speculate Moscow may be trying to press him towards a political settlement, though Damascus has dismissed any talk of differences with its ally and says the move is co-ordinated.

It was unclear what the withdrawal would mean for the outcome of the war or for the future of Assad.

The talks under way in Geneva are part of a diplomatic push launched with US-Russian support to end the five-year-long war that has killed more than 250,000 people, created the world's worst refugee crisis, and allowed for the rise of Islamic State.

US-Russian co-operation had already brought about a lull in the war going into the talks via a "cessation of hostilities agreement" that led to a sharp decline in fighting between rebels and the government in western Syria.

But the Syrian government, which had been losing ground to rebels before Russia intervened, had indicated it was no mood to compromise on the eve of the talks, calling the presidency a "red line" and ruling out a negotiated transfer of power.

The main opposition delegation wants Assad out of power by the start of a political transition.

While some rebels have expressed guarded optimism at Putin's announcement, others doubt Moscow is about to abandon the Syrian leader.